1. Field
Exemplary embodiments of the present invention relate to a substrate for an electrowetting display device and a method of manufacturing the substrate. More particularly, exemplary embodiments of the present invention relate to a substrate for an electrowetting display device having an improved manufacturing reliability and a method of manufacturing the substrate.
2. Discussion of the Background
An electrowetting display device displays an image by using an aqueous liquid and a non-aqueous liquid. Generally, the electrowetting display device includes a first substrate on which a pixel electrode is formed, a second substrate on which a common electrode is formed, an aqueous liquid interposed between the first and second substrates, and a non-aqueous liquid disposed at each of the pixel electrodes. When a voltage is applied between the pixel electrode and the common electrode, a surface tension of the aqueous liquid is varied so that the non-aqueous liquid is moved to transmit or block light. Thus, the electrowetting display device may display an image.
Because the non-aqueous liquid has a different polarity from the aqueous liquid, the non-aqueous liquid disposed at each pixel has a droplet state. The non-aqueous liquid droplets disposed adjacent to each other are divided by a partition wall formed on the first substrate dividing the pixels. Light is transmitted through the non-aqueous liquid in a state such that when the non-aqueous liquid is dispersed to cover the pixel, the electrowetting display device displays a black image. Alternatively, when the non-aqueous liquid is concentrated at the partition wall, light is transmitted through the pixel.
In order to prevent the aqueous liquid from being infiltrated into elements (i.e., a pixel electrode or a thin-film transistor connected to the pixel electrode) formed on the first substrate to damage the pixel electrode or the thin-film transistor, a water-repellent layer is formed on a substrate on which the pixel electrode and the thin-film transistor are formed, and then the partition wall is formed on the water-repellent layer.
However, when the partition wall is directly formed on the water-repellent layer, the partition wall is stripped from the water-repellent layer as a result of a strong hydrophobic property of the water-repellent layer. Moreover, it is difficult to form a photoresist layer for forming the partition wall on the water-repellent layer. In order to solve the above problems, a surface treating process forming a fine concave-convex shape on a surface of the water-repellent layer is performed. However, the photoresist layer partially remains on the water-repellent layer after forming the partition wall as a result of the concave-convex shape, so that the remaining photoresist layer affects a movement of the aqueous liquid and the non-aqueous liquid. Thus, the display quality of the electrode wetting display device and a manufacturing reliability of a product are reduced.